JP2015077026A - Non-contact power supply mechanism and secondary coil for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-contact power supply mechanism having high power supply efficiency.SOLUTION: A secondary coil 3 is provided on a power reception device that supplies power to an electric apparatus, whereas a primary coil is provided on a power supply device that supplies power to the power reception device. The primary coil includes: a primary core composed of a magnetic material; and a winding composed of a conductive material and wound around the primary core. The secondary coil 3 includes: a rod-shaped secondary core 31 composed of a magnetic material; a winding 32 composed of a conductive material and wound around the secondary core 31; and a magnetic sheet 4 attached to at least one end face of the secondary core 31. The magnetic sheet 4 includes: a close contact part 41 being in close contact to an end face 31a of the secondary core 31; and a bent part 42 extending from the close contact part 41 to the radial direction of the secondary core 31, and having a normal which is at least partially not in parallel with the axial core direction of the secondary core 31.

Description

  The present invention relates to a contactless power supply mechanism, and more particularly to a contactless power supply mechanism using electromagnetic induction and a secondary coil used therefor.

  Conventionally, cordless electrical devices such as mobile devices such as mobile phones have built-in rechargeable batteries and are charged using charging devices such as cradle and AC adapter. In such a charging system, power supply and charging are performed by bringing a contact on the electric device side and a contact on the charging device side into contact with each other and making them electrically conductive.

  In recent years, a non-contact power feeding (non-contact power feeding) method in which power is fed without bringing the contacts into contact with each other has been adopted. In the non-contact power feeding method, since there are no contacts exposed to the outside, there is no risk of contact failure, and waterproofing is easy.

  Currently, the electromagnetic induction method, the radio wave method, and the electromagnetic resonance method are used for non-contact power feeding. In the electromagnetic induction method, a secondary coil is provided on the electric device side, and a primary coil is provided on the power supply device side. When power is supplied from the power supply device to the electric device, the power supply device and the electric device are arranged so that the primary coil and the secondary coil face each other. And an electric current is supplied to a primary coil and a magnetic flux is generated in a primary coil. This magnetic flux generates an electromotive force due to electromagnetic induction in the secondary coil. Thereby, an electric equipment can receive electric power supply.

  In a conventional electromagnetic induction type non-contact power feeding mechanism, a primary coil and a secondary coil as shown in Patent Document 1 are formed as spiral planar coils, and these are opposed to each other during power feeding.

  In Patent Documents 2 and 3, the secondary coil is formed in a rod shape (arc shape), and both end portions of the secondary coil are sandwiched between the end portions of the primary coil.

JP 2012-199505 A Japanese Patent Laid-Open No. 9-238428 JP 2005-137173 A

  However, when a planar coil as in Patent Document 1 is used, there is a problem in that power supply efficiency is reduced due to the displacement of the coil. Further, even when a coil having a configuration as described in Patent Documents 2 and 3 is used, the magnetic flux acting on the secondary coil becomes stronger, but when the secondary coil is displaced or rotated with respect to the primary coil. The power supply efficiency may be reduced.

  The present invention has been made in view of the above problems, and an object thereof is to provide a non-contact power feeding mechanism with high power feeding efficiency.

  In a preferred embodiment of the contactless power supply mechanism of the present invention, the power supply device includes: a power receiving device that supplies power to an electrical device; and a power supply device that supplies power to the power receiving device. The power receiving device includes a secondary coil, and the primary coil includes a primary core made of a magnetic material, and a winding made of a conductive material and wound around the primary core. The coil includes a rod-shaped secondary core made of a magnetic material, a winding made of a conductive material, wound around the secondary core, and a magnetic sheet attached to at least one end face of the secondary core. The magnetic sheet is in close contact with the end face of the secondary core, and extends in the radially outward direction of the secondary core from the close portion, and at least partially parallel to the axial direction of the secondary core. A bend having a normal that is not .

  In this configuration, a magnetic sheet including a close contact portion and a bent portion is provided on the end surface of the secondary core. Therefore, even if the axial center direction of the secondary core rotates with respect to the magnetic flux direction generated by the primary coil, magnetic flux that cannot be used when using the conventional secondary coil also enters the bent portion of the magnetic sheet, It flows into the secondary core through the close part. Therefore, even if the axial direction of the secondary core rotates with respect to the direction of the magnetic flux generated by the primary coil, it is possible to suppress a decrease in power supply efficiency. Thereby, the freedom degree of arrangement | positioning of the secondary coil with respect to a primary coil can also be raised.

  In one of the preferred embodiments of the contactless power feeding mechanism of the present invention, the primary core includes a pair of facing portions configured such that the axial centers thereof are parallel and a space is formed between each other, The secondary coil is disposed between the pair of opposed portions in a power feeding state, and the magnetic sheets are provided on both end faces of the secondary core.

  According to this structure, while increasing the magnetic flux which acts on a secondary coil, the fall of electric power feeding efficiency by rotation with respect to the magnetic flux method which the primary coil generate | occur | produces in the axial center direction of a secondary core can be suppressed.

  Although the shape of the bent portion can be variously changed, it is preferable that the side cross-sectional shape is an arc shape because there is a portion where the magnetic flux is orthogonally incident at any rotation angle. Furthermore, if the bent portion is spherical, a reduction in power supply efficiency can be suppressed with respect to various rotation angles.

  In a preferred embodiment of the secondary coil for contactless power supply mechanism of the present invention, the secondary coil for contactless power supply mechanism that generates magnetic force by receiving magnetic flux from the primary coil provided in the power supply apparatus, A rod-shaped secondary core made of a material, a winding made of a conductive material, wound around the secondary core, and a magnetic sheet attached to at least one end face of the secondary core, and the magnetic The sheet has a close contact portion that is in close contact with the end surface of the secondary core, and a normal that extends from the close contact portion in a radially outward direction of the secondary core and is at least partially not parallel to the axial direction of the secondary core. And a bent portion. Such a secondary coil can also apply the additional characteristic structure of the above-mentioned non-contact electric power feeding mechanism, and has the same effect.

It is the schematic of a non-contact electric power feeding mechanism. It is an enlarged view of the opposing part of a primary coil. It is the schematic of a power receiving apparatus. It is a figure explaining the influence of the position shift (rotation) of the secondary coil with respect to a primary coil. It is a figure explaining the influence of the position shift (rotation) of the secondary coil with respect to a primary coil. It is a figure explaining the influence of the position shift (rotation) of the secondary coil with respect to a primary coil. It is a figure showing arrangement | positioning of the magnetic sheet with respect to the secondary coil in another embodiment. It is a figure showing arrangement | positioning of the magnetic sheet with respect to the secondary coil in another embodiment.

  The contactless power supply mechanism in the present embodiment will be described below with reference to the drawings. FIG. 1 is a schematic diagram of a non-contact power feeding mechanism in the present embodiment. As shown in the drawing, the non-contact power feeding mechanism includes a power receiving device B that supplies power to an electrical device (not shown) and a power feeding device A that supplies power to the power receiving device B. The power feeding device A supplies power to the power receiving device B by electromagnetic induction. The power feeding device A is built in, for example, a power supply device such as a charger connected to commercial power. On the other hand, the power receiving device B is built in an electric device such as a mobile phone, a mobile terminal, and an electric toothbrush.

[Power supply device]
The power feeding device A includes a primary coil 1 and a power feeding circuit 2 that drives the primary coil 1 with power from a commercial power source or the like. The primary coil 1 includes a primary core 11 made of a magnetic material such as ferrite and a winding 12 made of a conductive material and wound around the primary core 11. Since the configuration of the power feeding circuit 2 is well known, description thereof is omitted.

  The primary core 11 in this embodiment includes a base portion 11a, a pair of extending portions 11b, and a pair of opposing portions 11c. A pair of extension part 11b is extended from each of the both ends of the base 11a. Moreover, the opposing part 11c is extended so that it may mutually oppose from the edge part of each extension part 11b. A space S is formed between the end surfaces 11d of the pair of opposed portions 11c. In the present embodiment, the pair of end faces 11d are configured to be parallel and opposed to each other.

  As shown in the figure, in the present embodiment, the base portion 11a, the extending portion 11b, and the facing portion 11c are all arc-shaped and are smoothly connected to each other. Such a primary core 11 can be manufactured by cutting a part of the toroidal core. In order to make the pair of end faces 11d parallel and face each other, the cutting center may be cut so that the front and rear sides of the cutting center are uniform and the cutting surfaces are parallel. Thus, if the primary core 11 is formed by cutting a part of the toroidal core, the primary core 11 can be manufactured at low cost.

  As described above, the pair of opposing portions 11c are configured to oppose each other, but more specifically, are configured such that the axis centers thereof are parallel to each other. Here, the term “parallel” includes not only strict parallelism but also a case where the axes of each other intersect at a minute angle δ.

  FIG. 2 is an enlarged view of the vicinity of the facing portion 11 c of the primary core 11. As described above, since the facing portion 11c in the present embodiment is arcuate, the axis is also arcuate. However, the facing portion 11c can be divided into minute regions, and the axial center direction in each minute region can be approximated by the tangential direction in each minute region. For example, the axial direction of the end surface 11d is the tangential direction of the facing portion 11c of the end surface 11d. In FIG. 2, the tangential direction of the end face 11d is represented as the axial direction of the facing portion 11c. As shown in the figure, in the primary core 11 of the present embodiment, the respective axial centers x1 and x2 of the pair of opposed portions 11c intersect at a minute angle δ. In such a case, the axial centers of the pair of opposed portions 11c are considered to be parallel.

[Power receiving device]
As shown in FIG. 3, the power receiving device B includes a secondary coil 3 that generates an electromotive force based on the magnetic flux generated by the primary coil 1. The secondary coil 3 is connected to a power receiving circuit (not shown), and the electromotive force of the secondary coil 3 is converted into electric power by the power receiving circuit.

  The secondary coil 3 includes a secondary core 31 made of a magnetic material such as ferrite and a winding 32 made of a conductive material and wound around the secondary core 31.

  A magnetic sheet 4 is provided on the end surface 31 a of the secondary core 31. As shown in the figure, the magnetic sheet 4 includes a close portion 41 that is in close contact with the end surface 31 a of the secondary core 31, and a bent portion 42 that extends from the close portion 41 in the radially outward direction of the secondary core 31. Yes. Note that the close contact in the present invention includes not only a state of being completely closely arranged but also a state of being arranged so as to have a slight gap (for example, 0.5 mm or less). Moreover, as shown in the figure, in this embodiment, the side cross-sectional shape of the bent portion 42 is an arc shape.

  In the non-contact power supply mechanism, it is necessary to increase the magnetic flux penetrating the secondary core 31 in order to increase the power supply efficiency. Therefore, when the secondary coil 3 without the conventional magnetic sheet 4 or the secondary coil 3 with the magnetic sheet 4 having only the close contact portion 41 is used, the axial direction of the secondary core 31 and the primary core When the axial direction (magnetic flux direction) of the 11 opposing portions 11c is parallel, the power supply efficiency becomes maximum, and when these relationships are not parallel, the power supply efficiency rapidly decreases. That is, when the axial direction of the secondary core 31 rotates with respect to the axial direction of the facing portion 11c of the primary core 11, the power supply efficiency is drastically reduced. In addition, the rotation angle in the following description means the rotation angle of the axial direction of the secondary core 31 with respect to the axial direction of the opposing portion 11c of the primary core 11, and the rotation angle of 0 ° is the secondary angle. This means that the axial direction of the core 31 and the axial direction of the facing portion 11c of the primary core 11 are parallel to each other.

  On the other hand, in the non-contact power feeding mechanism of the present invention, as shown in FIG. 4, the axial direction of the secondary core 31 of the secondary coil 3 and the opposing portion 11 c of the primary core 11, as in the conventional secondary coil. When the axial direction is parallel, the power feeding efficiency can be maximized. Further, as shown in FIGS. 5 and 6, even if the axial direction of the secondary core 31 of the secondary coil 3 rotates with respect to the axial direction of the opposing portion 11 c of the primary core 11, the magnetic flux is not magnetic. Is incident on the bent portion 42. The magnetic flux that has entered the bent portion 42 flows from the bent portion 42 to the close contact portion 41 and the secondary core 31, and then flows to the magnetic sheet 4 that is in close contact with the other secondary core 31. In order for the magnetic sheet 4 to receive the magnetic flux efficiently, it is desirable that the magnetic flux is orthogonally incident on the magnetic sheet 4, but the bent portion 42 of the present embodiment has a circular cross-sectional shape. Therefore, at least partially, the magnetic flux is orthogonally incident on the magnetic sheet 4. Therefore, by using the magnetic sheet 4 of this embodiment, even if the axial center direction of the secondary core 31 rotates with respect to the axial center direction of the opposing part 11c of the primary core 11, the fall of electric power feeding efficiency is suppressed. Can do.

  Note that the range of the rotation angle in which the reduction in power supply efficiency can be suppressed depends on the size of the central angle of the bent portion 42. For example, if the central angle of the bent portion 42 is 90 °, the axial center direction of the secondary core 31 rotates in the range of 0 ° to 90 ° with respect to the axial direction of the facing portion 11c of the primary core 11. However, there is no significant reduction in power supply efficiency unlike the conventional secondary coil.

  As described above, in the present invention, the magnetic sheet 4 composed of the close contact portion 41 and the bent portion 42 is brought into close contact with the end surface 31a of the secondary core 31 of the secondary coil 3, thereby suppressing a decrease in power supply efficiency. The degree of freedom of arrangement of the secondary coil 3 with respect to the primary coil 1 can be increased.

  7 and 8 show a secondary coil 3 provided with a magnetic sheet 4 having another configuration. In the magnetic sheet 4 of FIGS. 7 and 8, the close contact portion 41 and the bent portion 42 are both formed from a plane, but the normal line of the close contact portion 41 and the normal line of the bent portion 42 are not parallel. That is, the bent portion 42 is bent with respect to the close contact portion 41. The angle formed between the close contact portion 41 and the bent portion 42 is referred to as a bent angle. That is, the bending angle of the magnetic sheet 4 in FIG. 7 is an obtuse angle, and the bending angle of the magnetic sheet 4 in FIG. 8 is a right angle.

  When the magnetic sheet 4 having such a configuration is used, the power feeding efficiency becomes maximum when the rotation angle = 180 ° −bending angle, and decreases as the rotation angle is displaced from 180 ° −bending angle. . However, the power supply efficiency when the axial direction of the secondary core 31 rotates with respect to the axial direction of the opposing portion 11c of the primary core 11 is such a configuration as compared with the case where the conventional secondary coil 3 is used. The secondary coil 3 using the magnetic sheet 4 is higher. That is, if the secondary coil 3 provided with the magnetic sheet 4 configured as described above is used, even if the axial direction of the secondary core 31 rotates with respect to the axial direction of the opposing portion 11c of the primary core 11, Compared with the conventional secondary coil 3, it is possible to suppress a decrease in power supply efficiency.

[Another embodiment]
In the above-described embodiment, the primary core 11 has a pair of opposed portions 11c, and the secondary coil 3 is disposed in a space formed between them. However, the primary core 11 is replaced with the secondary core 31. Similarly, it may be formed in a rod shape and the primary coil 1 and the secondary coil 3 may be arranged to face each other. At this time, if the magnetic sheet 4 is provided on at least one end surface 31a of the secondary core 31, the above-described effects can be obtained.

  INDUSTRIAL APPLICABILITY The present invention can be used for a non-contact power supply mechanism of small electric devices such as a mobile phone, a mobile terminal, an electric toothbrush, and a wireless headset.

A: Power feeding device B: Power receiving device 1: Primary coil 11: Primary core 11c: Opposing portion 12: Winding 3: Secondary coil 31: Secondary core 31a: End surface 32: Winding 4: Magnetic sheet 41: Close contact portion 42 : Bending part

Claims (4)

A power receiving device for supplying power to the electrical equipment;
A power supply device for supplying power to the power receiving device,
The power supply device includes a primary coil,
The power receiving device includes a secondary coil,
The primary coil is
A primary core made of a magnetic material;
A winding made of a conductive material and wound around the primary core,
The secondary coil is
A rod-shaped secondary core made of a magnetic material;
A winding made of a conductive material and wound around the secondary core;
A magnetic sheet attached to at least one end face of the secondary core,
The magnetic sheet is
An intimate part in intimate contact with the end face of the secondary core;
A contactless power supply mechanism comprising: a bent portion extending from the close contact portion in a radially outward direction of the secondary core and having a normal line that is at least partially not parallel to the axial direction of the secondary core. The primary core includes a pair of facing parts configured such that the axes are parallel to each other and a space is formed between the primary cores,
The secondary coil is disposed between the pair of opposed portions in a power supply state,
The contactless power supply mechanism according to claim 1, wherein the magnetic sheet is provided on both end faces of the secondary core.   The contactless power supply mechanism according to claim 1, wherein the bent portion has an arc shape in a side section. A secondary coil for a non-contact power feeding mechanism that receives a magnetic flux from a primary coil provided in a power feeding device and generates an electromotive force,
A rod-shaped secondary core made of a magnetic material;
A winding made of a conductive material and wound around the secondary core;
A magnetic sheet attached to at least one end face of the secondary core,
The magnetic sheet is
An intimate part in intimate contact with the end face of the secondary core;
A secondary coil for a contactless power supply mechanism, comprising: a bent portion extending from the close contact portion in a radially outward direction of the secondary core and having a normal line that is at least partially not parallel to the axial direction of the secondary core.

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